Process of forming casings for stuffed products



June 11, 1946. F. H. REICHEL ET AL. 2,491,773 PROCESS OF FORMING A CASING FOR STUFFED-PRODUCTS Filed June 11, 1941 INVENTQRS Fran/r 1% 26/556/ Az/gwfustTCm/ar a the casing would have a definite dry size.

Patented June ill, 1946 PROCESS OF FORMING CASINGS FOR STUFFED PRODUCTS Frank H. Reichel and Augustus E. Craver, Fredericksburg, Va.,assignors to Sylvania In dustrlal Corporation, Fredericksburg, .Va., a corporation oi Virginia Application June 11, 1941,- Serial No. 397,552

12 Claims. 1

The present invention relates to a process for producing flexible tubing for use as a container for stufled products, for example, sausage.

Artificial sausage casings as heretofore made of cellulose hydrate are characterized by shrinking a substantial amount while drying from a waterswollen condition to an air-dry condition whereby the casing adheres closely to the encased food product and maintains the food product in a compacted condition and thereby presents an attractive appearance at all times. In order to preserve duringstufling.

A conventional prior procedure to control the size of casings furnished to meat packers has been to dry the casings while inflated to a given diameter by air or some other suitable gas so that When such prior casings were received by the packer, he would wet them in water, and while in the wet condition, a casing would he slipped or shirred over the stufllng horn of a stui'iing machine and the meat or other food product would be forced into the casing to fill and also to expand the casing to the size desired by the packer. The expension of the casing to the desired size by the food product required relatively high pressure, which was conducive to fatigue on the part of the stufling machineoperator who was required to hold the casing tightly around the stufling horn and against the pressure exerted by the food product. It was also necessary for the stuiier to strength of the casings being amplified in theireifect by the high stuiilng pressure. The above mentioned characteristics of prior cesin'gs great- 2 ly reduced the speed of production of the stufied products. Moreover. the finished product was frequently unsightly because of variation in size a and shape along the casing, particularly at the ends of the sausage or the like, in spite of all of the care that could be exercised by the machine operator, and considerable loss occasionally resulted due to bursting of the casings which had not been previously tested.

It is a general object of the present invention to provide a tubing, more'particularly a sausage ca inz. which will overcome all of the foregoing difilculties.

Another general object is to provide a process of making tubing, more particularly sausage cas-. ing, which can be stuflfed under a relatively low pressure.

A more specific object of the invention is to provide a tubing, more particularly'a casing, for stufled products which will require only a rela-' ings under a relatively low pressure.

It is a more specific object to provide a process of making a stufled sausage utilizing a casing which can be stufled under relatively low pressure and which will require relatively slight expansion during stumng.

in the art from the tollowing detailed description 1 of what are now considered the preferred embodiments of the invention.

The process of the present invention comprises, f

in generaL-eitpanding by application of an internal pressure, a tubing formed of a film-forming organic plastic material, in particular a filmforming cellulosicmaterial, while in a wet state to a predetermined diameter at least equal to and preferably greater than the diameter to which the casing will be expanded later during stufling by usual stufiing apparatus and in general accordance with usual stufiing operations. Thus by exassists pending the casing in the wet state to a 1 meter greater than that to which the casing will be er;- panded during stumng, the cg be tested during manufacture and decrease the possibility of failure during stumng. After such expansion, the pressure is released and the tubing is suitably dried, for example, in a flat uninflated condition, and is then cut into the desired lengths for studing. When the lengths of the tubing are wet by enable the elasticity of the casing to maintain the product in proper shape-free from bulges and wrinkles. This slight pressure will also expand the casing the small easily controlled amount necessary to bring the casing up to the desired stufied size,

The invention accordingly comprises the several steps and relation of one or more of such steps with respect to each of the others, which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

The film-forming organic plastic materials as a group may be employed in the tubing.

used in the present invention, and the following examples are given only by way of illustrating some members of this group which have been found most suitable: hydrcphilic colloids such as cellulose hydrate, alkali-soluble cellulose ethers,

, gelatine, casein and the like; also synthetic resins,

cellulose ethers, cellulose esters, cellulose etheresters, cellulose mixed esters, and the like, and mixtures of these substances. The cellulose by drate can be produced by regeneration from viscose, by the de-esterification oi'ceilulcse esters or by coagulation of cellulose from its solutions in organic and inorganic solvents such tier example as tetra-alkyl ammonium hydromdes, zinc chloride, alkali metal perchlorates, sulfuric acid and the like. Because of its superior strength, there is preferably employed tubing comprising cellulose hydrate obtained by the denitration of nitrocellulose, the expansion treatment hereinafter described being carried out after the denitration of the tubing and while it is in a wet state. When the tubing is made from viscose the expan sion thereof, according to this invention, is carried out after the regeneration of the cellulose hydrate, but while it is in a wet state.

It is to be understood that all expansion of the casing according to the present invention is independent of and distinct from any stretching to which the casing may have been subjected prior to denitration or prior to regeneration, as the case may be, for example, as disclosed in U. S. Patent No. 2,176,925. Any stretching of the tubing which is carried out before denitraticn or regeneration does not accomplish the novel results produced by expanding the casing after denitration or regeneration in accordance with the present invention.

The tubing which is to be expanded in accordance with the present invention may be produced in any well known manner, but preferably the tubing to be expanded by the present invention is produced according to said U. S. Patent No.

withdraws the nozzle from the casing.

One form of apparatus capable of use intcarrying out the process of the present invention is diagrammatically illustrated by the drawing. The

tubing 4, while in a wet state, passes between a pair of positively driven pinch rollers 6 which are urged toward each other under suitable adjustable pressure exerted by a suitable mechanism actuated by weighted levers, springs or the like in a well known manner sufiiciently to seal the tubing passing therethrough. The tubing 4 after leaving the pinch rollers 6 is passed between a second pair of positively driven pinch rollers 8 spaced some distance, for example, 4 to 8 feet from the rollers 6--6, the rollers 8 being also urged together under a suitable pressure in the I casing which extends between the pinch rollers 6 and 8-8 with a body of fluid such as liquid or as. By wrapping the open end of the casing about the nozzle and holding it tightly, the operator can impose the desired pressure vonthe body of fluid to expand the casing to the desired diameter. When the casing has attained the desired enlarged diameter, the operator lowers the upper pinch roller 8 into contact with the casing so as to pinch the casing between the rollers and seal it against leakage of the fluid and thereafter This leaves the body of fluid within the casing between the pinch rollers 5-5 and e-s to stretch the casing between these rollers as illustrated at d.

A body of gas, or liquid, or a solid mandrel may be used as the expanding medium but-a liquid is in many respects preferable. A liquid which has been found to be particularly desirable for expanding the casing is an aqueous solution a of a softening agent for the casing material. The

casing is expanded to a predetermined diameter which preferably is in excess of the diameter to p which the casing will be expanded during stuffby trial and a diameter is selecmd such that the casing, after drying and rewetting, will have a circumference smaller than the circumference to which it will be stufied. The difference between the rewet circumference and the circumference immediately after stumng is made as small as possible, having regard for the wall thickness of the casing and the physical characteristics of the material from which it is formed, so as to require a minimum stufing pressure and at the same time cause the elastic forces exerted by the casing during stufing to be sufficient to hold the product within the casing in a compact, shapely mass which is free from bulges such a would occur if the casing were not expanded at all during stumng. [in expansion to a diameter of between 5 anddo per cent greater than the diameter after stumng has been found to be satisfactory,

To support the weight of the liquid, a belt id ispositioned under the casing and is passed over rollers l2 and it which are positively driven so that the belt has the same peripheral speed as the casing. A tank is may be provided beneath the belt it to receive water discharged from the .casing t in. the event of a break in the casing.

' It is to be understood thatthe invention is not limited to stretching the tubing while it travels disclosed in United States application Serial No.

1 191,414. filed February 19, 1938, may be used in practicing the process of the present invention. In said prior application there is disclosed means for stretching organic plastic tubing while in the wet gel state comprising, in particular, means for maintaining a pressure differential between the inside and outside of a portion of the tubing while it is travelling continuously through the stretching zone. The pressure differential may be effected by the use of vacuum outside the tubing and/or fluid pressure within the tubing, or by the use of a'greater fluid pressure inside, as compared to a fluid pressure outside. Transverse stretching is more uniformly accomplished by exerting a fluid pressure within the tubing, as by the use of air or other gas, but preferably a liquid is employed which is a non-solvent oi the tubing material. The tubing may be stretched transversely also by an internally applied mechanical pressure, as by means of a solid mandrel.

The expanded tubing may be dried in any'suitable drier while avoiding wrinkling and distortion in general. For example, the casing may be dried by passing it in a sinuous path over and under a plurality of heated rollers of the type used in drying Cellophane, or preferably a drum drier of thetype described in United States Patent No. 2,070,252, to Borner, but preferably having larger drying drums than those shown in said patent. At the point A, the casing may be plasticized, spliced or otherwise treated before being dried.

. From the pinch rollers 8-8, the stretched wet casing is passed under a suitable guide roller II and is passed through an opening into a drier chamber 20 and then passed as many times as desired around positively driven relatively large drier drums 22 and 24 which are driven at substantially the same peripheral speed as the pinch rollers 8-8. The drums 22 and 24 maycom prise suitable wheel-like supports II which carry axially extending members II which may be slats lengths and stacked. The various driven members of the machine are driven in any desired manner from any one or more suitable prime movers.

vThe length of the run of the casing 4 through the drier chamber is made ofsufllcientiength, and the temperature of the drying medium. with. in the chamber is made sufficiently high,'for example, 180 F., to dry the casing l to any desired amount. The amount of moisture allowed to remaininthedrycasingwillvarywith different climatic conditions and different typu of material but for most purposes the casing will be found to be satisfactory if dried to between 6 and 10 per cent moisture content. The casing hrinks 7 during the drying step but to some extentthe shrinkage transversely a reduced by'the fact'tbat it is supported over a substantial part of its run by surface contact with the drier drums.

By making a preliminary test of the percentage of shrinkage of the normal casing upon drying while unrestrained, the amount of pre-expansion' can be varied to compensate for any part or all .of the subsequent shrinkage in the drier'or to cause the casing to have a larger diameter after, drying than before expansion.

The amount which the casing shrinks transversely during drying is of no particular significance since the dry size of the casing is not determinative of the finished size of the stuffed product in view of the fact that the casing is invariably wet and stuifed under pressure. The

casing may be dyed, printed or otherwise suitably marked with any desired indicia and/or configurations either before, during or after the expanding step and may be printed after drying.

when the casing is dried flat and there is a tendency for the walls of the casing to adhere, due possibly to lack of air within the casing, this condition can be overcome by passing the casing,

when the walls have been once separated in this manner there is no tendency for them to again sticktogether after reeling.

The apparatus used to carry out the process of the present invention may take many different forms and it is to be understood that the apparatus diagrammatically illustrated is for the purpose of explanation only and is not llmitative.

The tubing maybe plasticized or softened before, during or after expansion but before drying. It is preferred to expand the casing while in a wet state but before'plasticizing, since by deferring the plasticizing step until after the expanding step. the loss of plasticizer is avoided in the event that the tubing breaks while expand ing and, therefore, while being tested. Also, the thinner wall of the expanded tubing facilitates the plasticizing step in that less time is required for the plasticizer to penetrate entirely through the walls of the tubing. Any plasticizer or softener agent appropriate to the nature of the tubing material may be'used. For example, with cellulose hydrate tubing, the plasticizer may be an aqueous solution of glycerine, a glycol, sorbltol, or the like. The tubing maybe plasticized by passing it in a flat condition through a tank containing the plasticizins solution. For example, as by festooni'ng it over a plurality of rolls so that at least the lower portions of the loops of the tubing. pass into the pl'asticizing solution; or the tubing may have a plasticizing solution included on the interior of the tubing as well as on the exterior, or the plasticiains solution may be restricted to; the interior of the tubing only so as to avoid the formation of deposits of excess plasticizer on the exterior of the tubing and place the majority of the plasticizer on the interior of the tubingwhere it facilitates stufiing and later removal of the casing from the stuffed product, The absence of free glycerine deposits onthe external surface permits printing inks to spread uniformly and adhere tenaciously to the surface.

when the casings are received by the packer -of 16%. inches.

anon-res they are usually tied at one end and then soaked in water or some liquid which swells the casing material. The open end of the wet casing is slipped or shirred over the stufiing horn of any desired type of stumng machine. While the casing is so held tightly about the horn by one hand of the operator, the latter operates a pedal or sage meat from the stuifer and twists the casing to close the open end. While holding the twisted end of the casing, the operator then ties the twisted endor clips it in accordance with usual procedure to close the casing. The stuffed food product is then passed for further smoking and curing operations'ln accordance with well known prior art practices.

The small amount which it is necessary for the sausage meat to expand the casing in accordance with the present invention relieves the operator oi the effort heretofore required to hold the casing against a high pressure. For example, while stufling prior art casings, it has frequently been necessary to expand the casing in excess of 40 per cent. During stuffing of the easing in the present invention an expansion of to 18 per cent is all that is required to maintain the casing in tight contact with the casing filling at all times. For the purpose of illustrating the difierence between the stufling procedure required to stufi prior art casings and the casings of the present invention, reference is made to the following table in which the first circumference given for each casing is the circumference obtained after soaking the dried casing in water.

Each of the casings measured 10 inches in circurnference when in the wet, plasticized condition prior to drying and were dried in a hat uninflated condition.

Circumference in inches during stuffing The casing from which the above data was obtained was expanded by the internal pressure exerting liquid 60 per cent or to a circumference This high degree of expansion severely tested the casing for the existence of weak spots, pin-holes, etc. The casing was then .clried and in drying shrank to a circumference of 10 inches. The casing was then soaked in water, as a packer would do, whereupon the easing swelled to a circumference of approximately 12 /2 inches. It was then stuffed and the pressure required to expand the casing to the desired circumferential size for the stuffed product of lei/2 inches was only /3 of a pound as against 2%; pounds for the prior type casing. This light pressure expanded the casing of the invention 16 per cent which brought the casing up to the hired rwhereas, an expansion of 38 per cent was required to bring the prior type casin Per cent shrinkage after stumng (wet to air-dry state) Shrinkage Trans. Long.

iiittiiiiiuarassi::::::::::::::::;:: 332? $33 The amount of expansion required duringstuffing of the casing of the present invention does not require the exercise of skill formerly required to stuff casings in order to produce a casing h ving a given uniform size throughout its length. Furthermore, the low stuffing pressure required increases the life of the operating parts of the stuffing machine. Also, the low stufilng pressure involved in the use of the casing of the present invention relieves the stuffing machine Op rator of the necessity for holding the casing against a comparatively high pressure and reduces fatigue on the part of the operator, and thus enables the operator to produce more stuffed products in the course of a working day than was possible heretofore.

If desired, the casing may be stuffed following the expanding operation without drying the casing. The casing stuffed at this time may be plasticized before stuiiing or the plasticizer may be omitted if not desired.

One of .the outstanding contributions to the art oifered by the casing, of the present invention is the freedom of the casing from failures during stufingn. In this invention the casings are preferably expanded in the wet state well beyond the diameter to which they will belater expanded duringstufiing, therefore any weaknesses, pinholes or other defects within the casing will show up during the expanding operation and any breaks will occur at that time, thus insuring that all casings. which successfully pass the present prestretching operation without failure will withstand the low stuffing pressure encounmred unless they are damaged subsequently to testing. The pre-tested casing of the present inventiun reduces the waste of the food product which formerly occurred due to casing failures.

The casing of the present inveutionexpands the small amount required during stum s under a very low pressure and for this reason the easins wall near the ends of the casing expands abruptly from the tied portion instead of gradually as was the case heretofore and in this manner forms a square ended stuffed product which is much desired by merchants and cuswmers.

The casing of the present invention also simplifies stufiing operations to a point where a relatively unskilled operator may be used, which, of course, further reduces the expense of producing stuffed food products. Also the square end on the stuffed food product reduces loss during slicing because the size of the butt endv frequently cut oil and discarded is'reduced. Furthermore. the pie-expanded casing of the present invention has a relatively thin wall which causes the eas- The expression tire-expanded casing" or preexpanded tubing as used in the appended claims is intended to designate a casing or tubing which has been expanded alter denitration or regeneration and while in the wet state to a diameter at least equal to or greater than the diameter to which the casing will be expanded during stutting.

The casing of the invention may be used for all varieties of stuiled products and while particular reference has been made to .its use as a ing shall be interpreted as illustrative and not been described, what is products, the step comprising expanding during manufacture and prior to the initial drying a casing formed of a film-forming organic plastic material while in a wet gel state to an amount I greater than that to which the casing will be expanded during stufllng.

3. In a process of forming a casing for stuiIed products, the step comprising expanding during manufacture and prior to the initial drying a casing formed of a non-fibrous cellulosic material while in a wet gel state to an amount at least equal to that to which the casing will be expanded later during stuiilng.

4. In a process of forming a casing for stuiIed products, the steps comprising forming a regenerated cellulose casing from viscose, expanding said casing after regeneration and while in a wet gel state prior to the initial drying to a diameter at least equal to that to which the casing will be expanded later during stuiilng,' and drying said casing.

5. In -a process of forming a casing for stud products, the steps comprising forming a. casing from nitrocellulose, denitrating said casing, expanding the casing after denitration and while the casing is in a wet gel state prior to the initial drying to an amount at least equal to that to which the casing will be expanded later during stuiling. and drying said casing. v

6. Inaprocessrori'orming acasingiorstuired products,thestepscomprisingiormingacasing 10 from nitrocellulose, denitrating said casing, expanding the casing while in the wet gel state prior to the initial dryin by the application of internal hydraulic pressure to a diameter at least equalto that to which the casing will be expanded later during stumng, plasticizingthe casing, and drying said casing.

I 7. In a process for producing a stuiled .iood product, the steps comprising expanding during manufacture and prior to the initial drying a casing formed of a film-forming organic plastic material while in a wet gel state to an amount ing said casing and stufling sausage into said I at least equal to that to which the casing will be'expanded later during stuillng, drying said casing and'stufllng a food product into said casing.'

8. In a process for producing stuffed sausage. the steps comprising expanding a casing formed of a film-forming organic plastic material while in a wet gel state prior to the initial drying to an amount greater than that to which said casing will be expanded later during stui'ilng, drycasing.

9. In a process for producing a stuiled sausage having a desired stufled diameter, the steps comprising expanding a casing formed oi! a filmforming organic plastic material while in a wet gel state prior to the initial drying to a diameter at least equal to said stufled diameter, drying said casing and stufllng said casing with sausage meat to said desired diameter.

10. In a process for producing stuil'ed sausage. the steps comprising expanding a casing formed of a film iorming organic plastic material while in a wet gel state prior to the initial drying to a predetermined diameter, drying the casing and stumng said casing with sausage meat to a diameter less than said predetermined diameter.

11. In a. process for producing a stuil'ed food product, the steps comprising forming a tubing from a convertible non-fibrous film-forming material, converting the material of the tubing, expanding the converted tubing-while in a wet gel state prior to the initialdrying to an amount reater than that to which the tubing will be expanded later during stumng to test the tubing, drying said tubing and stuillng the tubing with the desired food product while expanding the tubing an amount less than that to whichthe tubing was previously expanded.

12. In a process for producing a stuiIed food product, the steps comprising expanding a, casing formed of a film-forming organic plastic material while in a wet state prior to'the initial drying to a diameter greater than that to which the casing will be expanded later during stufling, drying the casing, wetting the dried casing and stunlng a food product into said wet casing until the casing has a'diameter less than that to which the casing was pre-expanded during manuiacture. I

FRANK H. REICHEL AUGUSTUS E. CRAVER. 

